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Biological activity of a lipopolysaccharide extracted from Treponema hyodysenteriae
Abstract:
A lipopolysaccharide (LPS) was obtained from pathogenic Treponema hyodysenteriae by hot phenol-water extraction. Various effects of the LPS on host cells were examined in vitro. Toxicity for mouse peritoneal macrophages was observed after 10 h of incubation at concentrations as low as 15 micrograms of the LPS per ml. Marked enhancement of both complement (C3) and immunoglobulin G-Fc receptor-mediated internalization was noted in macrophages obtained from mice injected 6 days previously with 75 micrograms of the material. Incorporation of [3H]thymidine into murine splenocytes was elevated approximately fourfold when splenocytes were treated with 5 to 10 micrograms of LPS per ml. Incubation of the LPS with normal porcine serum resulted in the generation of a factor(s) that stimulated the migration of porcine leukocytes. Generation of the chemotactic activity was inhibited by heating the serum at 56 degrees C for 30 min before treatment with LPS. The results suggest that T. hyodysenteriae contains an LPS that is biologically active.
Insights
Pathogenic Treponema hyodysenteriae lipopolysaccharide (LPS) exhibits significant biological activity. This LPS impacts host cells, affecting macrophage function and stimulating leukocyte migration, indicating its potential role in disease.
Area of Science:
- Immunology
- Microbiology
Background:
- Pathogenic *Treponema hyodysenteriae* is a significant veterinary pathogen.
- Lipopolysaccharides (LPS) are key components of Gram-negative bacterial outer membranes and potent immune modulators.
Purpose of the Study:
- To isolate and characterize the lipopolysaccharide (LPS) from *Treponema hyodysenteriae*.
- To investigate the in vitro effects of this LPS on various host immune cells.
Main Methods:
- Hot phenol-water extraction was used to obtain LPS from *T. hyodysenteriae*.
- In vitro assays were performed using mouse peritoneal macrophages, murine splenocytes, and porcine leukocytes.
- Assays included toxicity, receptor-mediated internalization, [3H]thymidine incorporation, and leukocyte migration.
Main Results:
- *T. hyodysenteriae* LPS demonstrated toxicity to mouse macrophages at 15 µg/ml.
- LPS enhanced complement (C3) and IgG-Fc receptor-mediated internalization in macrophages from pre-injected mice.
- LPS stimulated [3H]thymidine incorporation in murine splenocytes and induced chemotaxis in porcine leukocytes, an effect inhibited by heat-inactivated serum.
Conclusions:
- *Treponema hyodysenteriae* contains a biologically active lipopolysaccharide.
- The isolated LPS modulates host immune cell functions, including toxicity, phagocytosis, proliferation, and migration.
- These findings highlight the potential immunomodulatory role of *T. hyodysenteriae* LPS in host responses during infection.